Mold for casting tubular shells.



`\ tain new and useful Improvement in Means fect fit being requisite thereto. 55

HENRYR. BAKER, OF NORTH ATTLEBOROUGH, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, OF ONE-HALF TO THE R. F. SIMMONS COMPANY# OF ATTLEBOROUGH, MASSACHUSETTS.

VIOLD FOR CASTING TUBULAR SHELLS. e

SPECIFICATION forming part of Letters Patent No. 665,865, dated January 15, 1901. Application filed January 10. 1900. Serial No. 943. (No model.)

To all whom, t may concern,.- and cheapen the method of manufacture and 5o Beit known that I, HENRY R. BAKER,a citithe rapidity of production, as well as toavoid zen of the United States, residing at North loss of time and material in finishing up the Attleborough, in the county of Bristol and interior surfaces of these shells preparatory to State of Massachusetts, have invented a ceruniting them to their base-metal cores, a perand Appliances for Manufacturing Tubular Referring to the drawings, S represents a Cast Shells of Gold or LikeMetal, of whichthe support or standard in which the mold is following isafull,clear, and exactdescription, seated or to which it is secured. As shown 1o reference being had to the drawings which acat S', this standard is bored transversely, and

company and form apart of this specification, a cross-pin P is tted in said standard, so as 6o in Which- Y to extend across the central opening S2. The

Figure lis a vertical section through the standard S is socketed at S3 to receive the middle of the apparatus whichl employ. Fig. hollow mold B, which is inserted at S4 and is 2 is a cross-section along the dotted line w w made to closely grasp the mold. Bis the holof Fig. 1, the supporting-standard S not being low mold or mold proper, which is shown in shown. Fig. 3 is a top view showing the cencross-section in Fig. 2. It is composed of two tral core and the pourhole;.and Fig, l is a lateral halves adjusted to each other by the cross-sectional View through w of Fig. l, dowels b l) b b, Figs. land 2.` The lower end zo showing in detail the construction of the nonof this mold is turned inward at B, so as to conducting core-covering E. make contact with and accurately center the 7o The lettering in all the figures is uniform. metal core A. The upper end of the mold B My invention relates to the manufacture of is left open, and in it is fitted the cap O, Figs. cylindrical or substantially cylindrical tubu- 1 and 3, which extends above the same and z5 lar shells of gold or other ductile metal or is centrally bored to accurately t the upper alloy, such as are used for the outer layers of end of the core A, which projects through it, compound ingots, the central core being of a and is also provided with a tapered pourdifferent and preferably a baser metal, the hole D, extended through said cap C and whole when formed up andthe different parts through which the molten metal is poured 3o united by solder or otherwise adapted to be into the hollow of the mold. Through the drawn down or otherwise reduced into wires center of the hollow center of this mold B ex- 8o or the like for the manufacture of articles of tends vertically7 the solid core A, made, prefjewelry, although my means and appliances erably, of polished steel and slightly tapered are adapted for the production of like shells from below upward, so that when the cross- 35 applied or capable of being applied to other pin P has been removed the said core can be purposes. In the manufacture of such tubudriven out of the cast-metal shell from above lar shells it is a matter of the highest impordownward.. At its lower end the core A is tance that the metal should remain homoprovided with a shouldered olfset A', making geneous after being completed and that the the lower portion somewhat larger in diame- 4o shells shall be free from seams, splits, or ter than the core above, and this enlargestrains,since otherwisewhenbeing reduced by ment accurately ts the corresponding per- 9o pressure applied from without to the comforation within the inturned lower ends of pound ingot the gold surface will draw irreguthe halves of the moldcasing B. Around larly upon the base-metal core and its thickthis steel core is placed, accurately fitted 45 ness will be variable, or it may be torn, split, thereto, a tubular covering of a slightly-elasor broken from the core altogether and alarge tic material which is a high insulator or nonexpense from loss be thereby incurred, not conductor of heat and which is also non-comonly in time and labor, but in the value of the bustible and which will not decompose, so as metal itself. My purpose also is to facilitate to generate gases when highly heated. For

, of this sheet of asbestos must not be overlapped or a seam will occur in the casting and the product be made defective. To avoid this, I take a strong sheet of brown and unsized paper, which I roll around the core and glue the layers of paper and asbestos together, so as to make a thin light roll of a single layer of paper, with'the ends flush against each other, or of two or more layers accurately fitted for evenness of overlap. I cut the asbestos sheeting to fit precisely around the core, the edges flush against each other and not overlapping, 'and I cement with mucilage or glue the asbestos covering to the paper lining, so that when drawn off the core they may be laid away until required for use.

*After forming the paper and asbestos roll upon the core and while still in place I rub 4the outer surface all over with paraffin, after which I sprinkle it thoroughly with powdered charcoal, which causes the molten metal to vrun easily and smoothly over the outside of the asbestos roll and leaves it when cool with a perfectly smooth inside. In casting my tubular shells I apply one of these asbestos and paper lined core-coverings to the slightly-tapered steel core A, sliding it on at its upper or thinner end and firmly seating it by means of the taper of the steel core, as already described. It will be seen in Fig. l that the asbestos covering and the shoulder A of the core at its lower end are below the upper margin of the inturned end of the mold B. By this means the asbestos covering is clamped and compressed by the two sides of the mold when brought together and it is not possible for any metal to escape around the core A, nor for contact to ltake place between the molten metal and the steel core. At its upper end, before the cap C is applied, the upper margin of the asbestos covering is constructed to fit closely to said cap C, and if it be too long I cut it off by a knife applied around the core, so as to make a close lit, and thereby exclude contact between the molten metal and the steel core at any part, while at the same time contact is madeon the outside in all parts between the molten metal and the inside of the mold B, which is made of steel, iron, or other suitable metal. In this way and by these means I am enabled to prevent chill of the inside of my cast-metal shell while in a tubular but molten state, the cooling proceeding from without inward and without strain orinternal splits or weak spots, which necessarily occur when the cooling or chill proceeds from both sides at the same time or from within outward without internal s upport while changing from a molten to a solid state. The contraction in cooling I also compensate for without strain by the elasticity of the interposed asbestos covering, so that by the use of my method and appliances much greater rapidity is secured and a more perfect shell obtained. The rapidity of production obtained over the use of sand cores is very great, as two or three dozen of these asbestos and paper coverings can be made during the time required to make one accurate sand core,the result being vastly superior besides. When the mold has been prepared, the molten metal is poured in Aat the pourhole D, and after cooling su fficiently the crosspin Pis pulled out, and by a blow on the projecting upper end of the steel core A the latter,bein g slightly tapered, as above described, drops down through the hole S2 in the support or standard S, and the mold-casing B being opened the shell is removed and the paper and asbestos lining is pulled out. A new covering is then slipped over the core A and the process repeated indefinitely. The method of manufacture is perfectly clean, the shells coming out with smooth inside' and outside surfaces and perfectly even texture throughout, only requiring a slight surfacing inside to adapt them to receive the base-metal cores in the manufacture of compound ingots, as already described.

I do not in my invention confine myself rigidly to the precise construction of the different parts of my appliances or the method of use as specifically set forth in this speciiication or drawings, but vary the same when required to meet the various circumstances of the special case, as would be done by any mechanic skilled in the art to which my in Vention pertains and without departing from the principles thereof as herein shown, described, and claimed.

Having now described my invention, what I claim, and desire to secure by Letters Patent, is-

1. The means for casting tubular shells of gold or the like consisting in an external hollow metallic mold, vertically divided into lateral segments detachable from each other, and adapted to be clamped together, means .for clam ping said segments together, comprising a base having a socket therein adapted to receive and hold said segments in position, a solid core longitudinally extended through said mold, and maintained in a definite position therein when said segments are clamped together, in combination with a detachable tube of asbestos sheeting interposed between the solid surface of said core and the space for cast metal in said metallic mold, substantially as and for the purposes described.

2. The means for casting tubular shells of gold or the like, consisting of a hollow metallic mold, vertically divided into two or more lateral segments detachable from each other having inturned lower lends and adapted to be clamped together, and a solid metallic core detachably fixed within said mold, parallel with said segments and held in place by said segments when clamped together, and, in com- IOO IIO

yl/oration S2, and detachable de'fent P, together with tubular core-covering E, of asbestos sheet, its lower end clamped between A and B', above A', substantially as described.

1li In combination with hollow mold, B, cap C, and core A, said mold formed of separate Vertical segments laterally detachable from each other, the tubular compound corecovering E, consisting of a tubular support of flexible fabric E', and a covering of soft asbestos sheeting E, said two layers noinontocl together and dried, said core-covering being A0E equal thickness throughout, and covered with an external facing of carbon or like substance,I said core-covering detachable from said Gore in tubular form, substantially as andv for the purposes described. l,

In testimony whereof 'I have hereunto affixed my signature this 6th day of January, A. D. 1900.

HENRY R. BAKER. Witnesses:

' HAROLD E. SWEET,

PHILIP E. BRADY.l 

